This relates to a system that facilitates positioning a tool in a work space or at a worksite, such as for example a construction site. When the interior of a building is being finished, connectors, anchors and the like are attached to the floors, ceilings and other structures in the building and cuts are made and holes drilled using power saws and drills. All of this must be accomplished using special power tools at predetermined locations, requiring that the tools be operated at numerous precisely defined positions in the building. For example, nail guns, power saws, powder anchor tools, and the like are used to nail, cut, install fasteners, and perform other operations at predetermined points within the building with little error. In any building, a large number of electrical, plumbing, and HVAC components must be properly sited and installed, usually with power tools. Additionally, finishing a building interior also requires that a number of different tools that are not powered be operated at precisely defined positions, such as for example reinforcement bar scanners. Positioning both power tools and non-power tools must be accomplished quickly and with some precision with respect to the surrounding walls, ceilings and floors as they are roughed in. Typically, it has required a significant amount of labor to lay out various construction points at such a construction site. Teams of workers have been needed to measure and mark predetermined locations. It will be appreciated that this process has been subject to errors, resulting from measurement mistakes and from accumulated errors. Further, the cost of this layout process and the time needed to perform the layout process have both been significant.
Various location determining systems, including systems that incorporate one or more robotic total stations, have been used for building layout. The total station in such a system, positioned at a fixed, known location, directs a beam of laser light at a retroreflective target. As the target moves, robotics in the total station cause the beam of light to track the target. By measuring the time of travel of the beam from the total station to the retroreflective target and then back to the total station, the distance to the target is determined. The directional orientation of the beam to the target is also measured. Since the dimensional coordinates of the total station are known, the dimensional coordinates of the retroreflective target can easily be determined. Based on the measured position of the retroreflective target, and the desired position of some building feature, such as a drilled hole, or a fastener, the operator can move the reflector to the desired position, and mark the position.
Although position determination systems, such as ranging radio systems and robotic total station systems, can facilitate and speed the layout process, nevertheless the layout process has continued to be lengthy, tedious, and expensive.